1. Field of the Invention
The present invention relates to an X-ray apparatus for irradiating an X-ray to an object (object to be radiographed) and, more particularly, to an X-ray apparatus in which a relative position of an X-ray source and a radiation element is optimized and an adjusting method of such an X-ray apparatus.
2. Description of the Related Art
Such a technique that an X-ray is one-dimensionally collimated by using a radiation element has been known. Japanese Patent Application Laid-Open No. 2000-137098 discloses solar slits having metal foils which are arranged on an X-ray radiation path and are laminated with an interval. Further, such a technique that a surface roughness is provided for the surface of the metal foil and a reflection of the X-ray is restricted, thereby forming a collimated X-ray beam has also been disclosed.
Japanese Patent Application Laid-Open No. 2004-89445 discloses such an X-ray generating apparatus that a collimator in which a plurality of micro capillaries are two-dimensionally arranged is combined with multiple X-ray sources arranged in a 2-dimensional lattice shape, thereby collimating the X-ray.
Japanese Patent Application Laid-Open No. H10-508947 discloses such a radiation system that a divergence X-ray appearing from an X-ray source having a small spot size is efficiently captured in a monolithic radiation element having a plurality of capillary tubes of hollow glass, thereby forming a pseudo collimated beam.
According to the radiation element disclosed in Japanese Patent Application Laid-Open No. 2000-137098, since only the collimated component of the X-ray is extracted, only an extremely minor part of the generated X-ray can be used and so use efficiency is low.
According to the radiation element disclosed in Japanese Patent Application Laid-Open No. 2004-89445, it is difficult to form the uniform capillaries. It is also difficult to two-dimensionally arrange the X-ray sources at a high density.
According to the radiation element disclosed in Japanese Patent Application No. H10-508947, since the capillary tubes of hollow glass are melted and molded together, it is difficult to form the uniform capillary tubes.
Therefore, a radiation element having such a simple structure that the generated X-ray is efficiently collimated and emitted is demanded.
In order to obtain the high-intensity X-ray and the high resolution, the relative position of the X-ray source and the radiation element is important. According to the technique disclosed in Japanese Patent Application Laid-Open No. 2000-137098, the alignment of the relative position of both of them is made so as to maximize the intensity of the X-ray which is transmitted through the solar slit. For example, in FIG. 10, when the X-ray source is moved in the y direction, if an X-ray source 1 exists within a range shown by broken lines, the intensity of the X-ray which is transmitted through a solar slit 31 becomes maximum and does not change. Since a magnitude of an angle width α hardly changes, an influence on the resolution of an image is also small. If the X-ray source 1 is out of the range of the broken lines, the intensity of the X-ray decreases. Therefore, such an alignment method that the intensity of the X-ray becomes maximum is used.
However, according to the foregoing alignment method, when the relative position of both of them is deviated from a design value, even if such a deviation is small and the decrease in intensity of the X-ray is not caused, there is a case where the resolution of the image decreases. Even in the other radiation elements in the related arts, according to the foregoing alignment method, there is a case where the resolution of the image deteriorates.
It is, therefore, an object of the invention to provide an X-ray apparatus in which a generated X-ray can be efficiently collimated and emitted by a simple structure and a best resolution of an image is obtained and to provide an adjusting method of such an X-ray apparatus.